In recent years, input apparatuses provided with a panel, such as a touch panel, touch switches or the like, have gained widespread use as input apparatuses that receive input operations from a user through operation units, switches and the like. These input apparatuses are used in mobile terminals such as mobile telephones, information devices such as calculators or ticket vending machines, household appliances such as microwaves, televisions or lighting appliances, industrial equipment (factory automation equipment), and the like.
A variety of types of such panels are known, including a resistive film type, a capacitive type and an optical type. All of these types of panels, however, receive input of a touch by a finger or stylus pen, and unlike push-button switches, the panels themselves are not physically displaced when touched.
Therefore, since the panel itself is not physically displaced when touched, the operator does not obtain any feedback for the touch input even though the input is received. As a result, the operator is likely to provide input repeatedly by touching the same position over and over, which may be stressful for the operator.
In order to prevent such repetitive input, some panels allow for auditory or visual confirmation of input operations by, for example, generating a sound upon receiving touch input or changing the display state by changing the display color of an image displayed on the display unit for an input object, such as an input button, at a position corresponding to the received input.
In the case of auditory feedback, however, confirmation becomes difficult in a noisy environment, and such feedback is not feasible if the apparatus is muted, as during silent mode. Furthermore, with visual feedback, if the size of the input object displayed on the display unit is small, the operator may not be able to confirm the change in display state, particularly when input is provided by finger and the input object is blocked from view by the finger.
A feedback method that is neither auditory nor visual but rather causes the panel to vibrate when the panel receives input, providing the operator's fingertip with a tactile sensation, has also been proposed (for example, see Patent Literature 1 and 2).